1. Field of the Invention
The present invention relates to a personal watercraft. More particularly, the present invention relates to a personal watercraft equipped with a cooling system of an engine and a cleaning system for cleaning the cooling system.
2. Description of the Related Art
In recent years, water jet-propulsion personal watercraft have been widely used in leisure, sport, or rescue activities. The personal watercraft is equipped with a water jet pump and an engine that drives the water jet pump in a space in an interior of the watercraft that is defined by a hull and a deck. The water jet pump operates to pressurize and accelerate water sucked from a water intake provided on a hull bottom surface and eject it rearward. Thereby, the watercraft obtains a propulsion force to move a body thereof. Typically, the personal watercraft is equipped with a cooling system configured to take in water from outside to cool the engine, etc, as disclosed in Japanese Laid-Open Patent Application Publication No. 2003-63497.
As shown in FIG. 11, the cooling system is configured to take in, as cooling water, a part of pressurized water such as sea water or lake water from inside the water jet pump through a water drawing pipe (cooling water pipe) 61 coupled to a pump casing of the water jet pump. The cooling water taken in is supplied to a cylinder block 63 of an engine 62, a cylinder head 64 of the engine 62, an exhaust passage such as an exhaust manifold 65, an exhaust pipe 66, and an expansion chamber 67, etc to cool these components. In this personal watercraft, the cooling water taken in from outside the watercraft cools the engine 62 and the exhaust passage. After that, some of the cooling water is discharged into a pump room for the water jet pump through a water discharge pipe 68 and the remaining cooling water is discharged outside the watercraft together with an exhaust gas through a water muffler 79 and an exhaust duct 70.
In addition to the water discharge pipe 68, the exhaust duct 70, and the cooling water pipe 61, the personal watercraft is provided with a second water discharge pipe 71 to effectively discharge the sea water or the lake water remaining in a cooling water passage after the watercraft is landed. The second water discharge pipe 71 is coupled to a region of the cooling water pipe 61 between the water jet pump and the engine 62. To be specific, the second water discharge pipe 71 is coupled to the region of the cooling water pipe 61 that is located upstream of the exhaust manifold 65 of the engine 62 and in close proximity to a filter 72 attached to the cooling water pipe 61. To enable the filter 72 to be easily accessed from outside the watercraft, the filter 72 is disposed at a relatively high location in the interior of an engine room. This inevitably lowers a region of the cooling water pipe 61 that is located between the filter 72 and the engine 62. The second water discharge pipe 71 is coupled at the above mentioned location to sufficiently discharge the water remaining in the lowered region of the cooling water pipe 61. A water outlet 71a of the second water discharge pipe 71 opens in a rear end surface of a hull.
In the personal watercraft including the cooling system constructed above, unwanted substances such as small stones or sea weed tend to remain in the cooling water passage or salt contained in the sea water tends to adhere to an inner wall surface thereof. To solve this, in the above personal watercraft, cleaning water is flowed into the cooling water passage from outside through the second water discharge pipe 71 to clean (hereinafter also referred to as flush) the interior of the cooling water passage. To be specific, cleaning water such as city water is supplied through the second water discharge pipe 71 from the water outlet 71a and is discharged from the water discharge pipe 68 or the exhaust duct 70 through the cooling water passage. The second water discharge pipe 71 serves as a cleaning water supply pipe and the water outlet 71a thereof serves as a cooling water inlet.
In the above personal watercraft, the water outlet 71a of the second water discharge pipe 71 is located at the rear end surface of the hull, and a coupling member by which the second water discharge pipe 71 is coupled to the cleaning water supply pipe protrude outward therefrom. Therefore, with the watercraft on a loading space of a trailer or a lift, the coupling member is difficult to access when coupling the cleaning water supply pipe to the second water discharge pipe. Because the bottom surface or a side surface of the hull is a planing surface, it is undesirable to protrude a member of the cleaning water inlet from these surfaces in order to avoid negative effect on planing capability. In addition, it is undesirable to mount the member which may spoil an external appearance of the watercraft.
Instead of forming the cleaning water inlet on an outer surface of the body, in a conventional method, a hatch cover or a seat is opened, an opening of the deck is opened, and a cleaning water supply hose is directly connected to a connecting port formed at the water cooling pipe of the engine to flush the cooling water passage. In this case, however, the hatch cover or the like must be opened while the cleaning water supply hose is connected to the cooling water passage. This undesirably causes a noise to be emitted outside from the engine.